@USBR: Aspinall Unit Forecast for Spring Operations: Current projected inflow to Blue Mesa Reservoir = 925,000 acre-feet

From email from Reclamation (Erik Knight):

The April 1 forecast for the April – July unregulated inflow volume to Blue Mesa Reservoir is 925,000 acre-feet. This is 137% of the 30 year average. Snowpack in the upper Gunnison River basin is currently 132% of average. Blue Mesa Reservoir current content is 259,000 acre-feet which is 31% of full. Current elevation is 7440 feet. Maximum content at Blue Mesa Reservoir is 829,500 acre-feet at an elevation of 7519.4 feet.

Black Canyon Water Right
The peak flow and shoulder flow components of the Black Canyon Water Right will be determined by the May 1 forecast of the April – July unregulated inflow volume to Blue Mesa Reservoir. If the May 1 forecast is equal to the current forecast of 925,000 acre-feet of runoff volume, the peak flow target will be 6,513 cfs for a duration of 24 hours. The shoulder flow target will be 915 cfs, for the period between May 1 and July 25. The point of measurement of flows to satisfy the Black Canyon Water Right is at the Gunnison River below Gunnison Tunnel streamgage at the upstream boundary of Black Canyon of the Gunnison National Park.

Aspinall Unit Operations ROD
Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the peak flow and duration flow targets in the lower Gunnison River, as measured at the Whitewater gage, will be determined by the forecast of the April – July unregulated inflow volume to Blue Mesa Reservoir and the hydrologic year type. At the time of the spring operation, if the forecast is equal to the current forecast of 925,000 acre-feet of runoff volume, the hydrologic year type will be set as Moderately Wet. Under a Moderately Wet year the peak flow target will be 14,350 cfs and the duration target at this flow will be 10 days. The duration target for the half-bankfull flow of 8,070 cfs will be 20 days. The criteria have been met for the drought rule that allows half-bankfull flows to be reduced from 40 days to 20 days.

Projected Spring Operations
During spring operations, releases from the Aspinall Unit will be made in an attempt to match the peak flow of the North Fork of the Gunnison River to maximize the potential of meeting the desired peak at the Whitewater gage, while simultaneously meeting the Black Canyon Water Right peak flow amount. The magnitude of release necessary to meet the desired peak at the Whitewater gage will be dependent on the flow contribution from the North Fork of the Gunnison River and other tributaries downstream from the Aspinall Unit. Current projections for spring peak operations show that flows in the Gunnison River through the Black Canyon could be over 7,500 cfs for 10 days in order to achieve the desired peak flow and duration at Whitewater. With this runoff forecast and corresponding downstream targets, Blue Mesa Reservoir is currently projected to fill to an elevation of around 7500 feet with an approximate peak content of 660,000 acre-feet.

Aspinall Unit dams

#Runoff in #ColoradoRiver basin likely below-average, @usbr official warns — @AspenJournalism #snowpack #COriver #aridification #cwcac2019

A big beach on the banks of the Green River in September 2018, one of the lowest months on record for inflow into Lake Powell. Runoff is 2019 is expected to be better than 2018, but still below average due to dry soil conditions in the area drained by the Green and Colorado river systems. Photo: Brent Gardner-Smith/Aspen Journalism

From Aspen Journalism (Brent Gardner-Smith):

The regional director of the Upper Colorado River Basin for the Bureau of Reclamation told water managers and users last week to expect below-average runoff this year, despite encouraging snowfall this winter.

Brent Rhees — who oversees the federal reservoirs in the upper basin for the Bureau of Reclamation, including Lake Powell, Flaming Gorge and Blue Mesa — said that although this winter’s snowfall, or “snow water equivalent,” in the upper basin above Lake Powell was now above average (109 percent on Feb. 7) the parched ground left in the wake of a hot, dry 2018 likely would soak up a lot of the resultant moisture in the spring.

As such, this year’s runoff is not expected to reach the average level, although storms in February and March could push it up to the 80 percent range.

“What we’re suffering from is last year’s dry year,” Rhees told the members of the Colorado Water Congress on Feb. 1. “And so, the runoff that is forecast is not that great. Last year, you all remember, it was the third-lowest on record inflow into Lake Powell. So, it’s not looking really good.”

Since Rhees’ remarks, it has been snowing a lot in Colorado, and the snowpack in the Roaring Fork River basin was at 115 percent of average on Feb. 6. But, again, Rhees was looking at future runoff over a thirsty landscape.

The inflow into Lake Powell during water year 2018 (Oct. 1 to Sept. 30) totaled about 4.5 million acre-feet, or MAF, while about 9 MAF was released from Glen Canyon Dam to run down the Colorado River and into Lake Mead, Rhees said.

“So, the math is pretty simple, isn’t it?” Rhees said. “More went out than came in. And so, we saw a significant drop in reservoir elevation.”

As of Jan. 1, the Bureau of Reclamation forecast that 6.98 MAF, or 64 percent of average, would most likely flow into Lake Powell, but releases from Lake Powell are expected to be about 8.6 MAF.

“We’re going to release a little bit more than comes in, likely this year,” Rhees said.

That means Lake Powell is expected to continue to shrink in 2019.

On Feb. 3, the elevation of the reservoir, as measured against the upstream face of Glen Canyon Dam, was 3,575 feet above sea level, or 39 percent full, and held 9.6 MAF.

A diagram showing the intake structures on the upstream face of the Glen Canyon Dam, which forms Lake Powell.

Three efforts

The first ongoing effort to bolster water levels in Lake Powell is weather modification in the form of cloud seeding.

Rhees said the federal government’s position on funding cloud seeding has moved from funding only research to funding active operations, too.

“That’s good news from my perspective,” he said.

The second effort is “drought-response operations,” which will begin if Lake Powell drops to the triggering elevation of 3,525 feet, or 35 feet above minimum power pool (which it is not yet forecasted to do in either 2019 or 2020).

But should the reservoir hit 3,525 feet, the drought-response operations will entail releasing up to 2 MAF of water from federal reservoirs in the upper basin, primarily from Flaming Gorge Reservoir on the Green River, which can hold 3.7 MAF; Blue Mesa Reservoir on the Gunnison River, which can hold 829,500 acre-feet; and Navajo Reservoir on the San Juan River, which can hold 1.69 MAF.

Rhees said Flaming Gorge is “the one that can have the biggest impact, (but) all (federal) reservoirs can participate in propping up that minimum power pool of 3,490 (feet).”

He also said the releases from the reservoirs would be “indiscernible” to river users and the water would not come down the river in a big wave of water, as some might imagine.

“You won’t know, if you are on the river, that it’s even happening,” he said.

The third effort to add more water to the river system is “demand management,” or a purposeful reduction in the amount of water diverted from rivers and put to a consumptive use, such as growing a crop or a lawn.

Voluntary demand-management programs are now being investigated in Colorado, Utah and Wyoming, and the water saved by irrigators fallowing fields — for money — is to be stored in a new regulatory pool of up to 500,000 acre-feet in Lake Powell.

Editor’s note: Aspen Journalism covers rivers and water in collaboration with The Aspen Times and other Swift Communications newspapers. The Times published this story on Thursday, Feb. 7, 2018.

Aspinall Unit operations meeting January 17, 2019

From email from Reclamation (Erik Knight):

The next Aspinall Operations meeting will be held on January 17th in Montrose at the Holiday Inn Express. The meeting will start at 1:00.

Aspinall Unit

Western Slope Water Summit recap

Gunnison River Basin via the Colorado Geological Survey

From The Montrose Daily Press (Andrew Kiser):

Farmers have a taxing job growing crops due to water rights and, now, a multi-year drought, said Montrose County Commissioner Sue Hansen.

Those concerns were brought to the forefront during the Western Slope Water Summit — held Tuesday morning at the Montrose County Event Center. The group mostly discussed the water shortage and the drought crisis on the Western Slope.

Hansen said the county wanted farmers and producers to know about those challenges and about other potential obstacles under the new drought contingency plan…

As far as the effects of the drought, residents need look no further than the Gunnison River.

According to the Colorado River District, the river is snared between climate change-driven drought and overuse by the Lower Basin states to which a sure quantity of water must be transported each year, under the 1922 Colorado River Compact…

Andy Mueller, Colorado River District general manager, added the state’s farmers “are battling urban areas for their livelihood.”

“I think we, as an Upper Basin, need to put the hammer down and need to call them out in terms of what they’re doing,” he said.

Blue-Green algae found in Blue Mesa Reservoir

Graphic credit: Climate Central

From the Associated Press via The Grand Junction Daily Sentinel:

The National Park Service says unsafe levels of a type of algae that can be harmful to humans have been found in the water of a central Colorado reservoir.

Park officials said they detected the presence of toxins that can be produced by algae blooms in water samples taken from Blue Mesa Reservoir.

The agency advised visitors to avoid contact with shallow waters in an area known as the Iola Basin and to avoid mats of algae throughout the reservoir.

The reservoir is part of Curecanti National Recreation Area west of Gunnison, Colorado.

Harmful blue-green algae is natural to the area but can spread quickly in warm, shallow water.

Forecast for Blue Mesa Reservoir = record low territory #ColoradoRiver #COriver #aridification

From The Colorado Springs Gazette (Liz Forster):

The Blue Mesa Reservoir, which feeds into the Colorado River, is at 39 percent capacity, according to the Bureau of Land Reclamation. The last time the reservoir west of Gunnison was at a similar level was in 1987, said Sandra Snell-Dobert, a spokeswoman for the Black Canyon of the Gunnison National Park and Curecanti National Recreation Area.

Soon, water levels are expected to drop to the point where launching and operating boats at most ramps won’t be possible, Snell-Dobert said

Low water levels and rising temperatures also have allowed for blue-green algae blooms. Although no direct environmental impacts have not been observed, some species of this algae can produce toxins that are harmful to dogs.

The Gunnison River Basin varied between 50 percent and 80 percent of its average snowpack this winter, hitting a low of 51.6 percent Dec. 20 and a peak of 79.81 percent April 20.

Other Colorado River reservoirs are facing similar shortages.

Lake Powell and Lake Mead in Arizona dropped to dangerous levels this week because of what scientists are calling the effects of the Colorado River’s worsening “structural deficit,” The Associated Press reported.

Lake Powell and Lake Mead hit 48 percent and 38 percent capacity, respectively.

The Colorado River basin, which feeds lakes Mead and Powell, has been drying out over the last two decades, scientists said. With the demands from farms and cities exceeding the available water supply, the strains on the river and reservoirs are being compounded by growing population, drought and climate change.

From Colorado Public Radio (Grace Hood):

The Colorado Division of Water Resources reports the basins were 50 percent full at the end of August, in contrast to last year’s 120 percent average capacity. The average for this time of year is about 82 percent.

The Yampa-White, San Juan-Dolores, Rio Grande, Gunnison and Colorado river basins are classified as being in either “moderate” or “severe drought.”

The Blue Mesa Reservoir near Gunnison on the Curecanti National Recreation Area, is near historic lows — it’s 39 percent full — and has closed almost all its boat ramps. Iola closed Thursday night, the Lake Fork ramp closes Monday. That will leave only the Elk Creek ramp on the reservoir’s north shore along Hwy. 50 open, said recreation area spokeswoman Sandra Snell-Dobert. “Elk Creek, the ramp will remain open as long as we can keep it open.”

The last time water levels were this low on the reservoir was in 1987, Snell-Dobert said. Blue Mesa usually only closes if there’s not enough staff or if the reservoir freezes. The reservoir levels now have also caused some abnormal boating hazards.

“Mostly it’s rocks that are becoming exposed as the water level decreases. There are a lot of rock promontories and islands, and those kinds of things that we haven’t seen in a long time,” she said. But despite the boating restrictions, Snell-Dobert said shoreline fishing, kayaking, canoeing and other hand-launched, non-motorized boating are still allowed at the reservoir.

Aspinall Unit operations update: Inflows to Blue Mesa Reservoir April-July = 35% of average

Blue Mesa Reservoir

From email from Reclamation (Erik Knight):

Releases from the Aspinall Unit will be decreased by 75 cfs on Sunday, September 9th. Releases are being decreased in order to bring flows in the lower Gunnison River closer to the baseflow target while conserving storage in Blue Mesa Reservoir. The actual April-July runoff volume for Blue Mesa Reservoir was 237,500 AF of inflow, which is 35% of average.

Flows in the lower Gunnison River are currently above the baseflow target of 890 cfs. River flows are expected to stay above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 890 cfs for September.

Currently, diversions into the Gunnison Tunnel are 1000 cfs and flows in the Gunnison River through the Black Canyon are around 575 cfs. After this release change Gunnison Tunnel diversions will still be 1000 cfs and flows in the Gunnison River through the Black Canyon will be around 500 cfs.